Lecture Notes by Christopher Lay

Los Angeles Pierce College

Department of History, Philosophy, and Sociology

 

 

 

 

Mathew Van Cleave's 2016 Introduction to Logic and Critical Thinking

 

https://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=457

 

 

 

 

Chapter 4 "Informal fallacies", § 2 "Slippery Slope Fallacies"

"Slippery slope fallacies depend on the concept of vagueness." 

 

"When a concept or claim is vague, it means that we don’t know precisely what claim is being made, or what the boundaries of the concept are."

 

 

 

 

 

 

 

 

 

 

Sorites [Heap] Paradox

"The classic example used to illustrate vagueness is the 'sorites paradox.' The term 'sorites' is the Greek term for 'heap' and the paradox comes from ancient Greek philosophy."  

 

"Here is the paradox. I will give you two claims that each sound very plausible, but in fact lead to a paradox.  Here are the two claims:  1. One grain of sand is not a heap of sand.  2. If I start with something that is not a heap of sand, then adding one grain of sand to that will not create a heap of sand." 

 

"By continuing to add one grain of sand over and over, I will eventually end up with something that is clearly a heap of sand, but that won’t be counted as a heap of sand if we accept both claims 1 and 2 above." 

 

 

 

 

 

 

 

 

 

Our Point

"Philosophers continue to argue and debate about how to resolve the sorites paradox, but the point for us is just to illustrate the concept of vagueness." 

 

 

 

 

 

 

 

 

 

Other Examples

There "are so many [vague] concepts, such a color concepts (red, yellow, green, etc.), moral concepts (right, wrong, good, bad), and just about any other concept you can think of." 

 

 

 

 

 

 

 

 

 

Exceptions

"The one domain that seems to be unaffected by vagueness is mathematical and logical concepts." 

 

 

 

 

 

 

 

 

 

Relevant Fallacies

"There are two fallacies related to vagueness: the causal slippery slope and the conceptual slippery slope."

 

 

 

 

 

 

 

 

 

Reflect

What concepts can you think of that exemplify this worry?